122 lines
3.0 KiB
C
122 lines
3.0 KiB
C
#ifndef LIBABACUS_REFCOUNT_H
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#define LIBABACUS_REFCOUNT_H
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#include "result.h"
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#include "gc_functions.h"
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/**
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* A struct for holding
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* the number of references
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* to a value, as well as the function required
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* to free the value.
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*/
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struct libab_ref_count_s {
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/**
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* The value this reference holds.
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*/
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void* data;
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/**
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* The fucntion to free the value.
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* Can be NULL for no-op.
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*/
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void (*free_func)(void* data);
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/**
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* The number of references that
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* prevent the deallocation of the value.
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*/
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int strong;
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/**
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* The number of references
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* that still exist, even to a freed instance.
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*/
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int weak;
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/**
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* The number of outside references.
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* This is used for garbage collection.
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*/
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int gc;
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/**
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* Previous pointer for garbage collection
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* linked list.
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*/
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struct libab_ref_count_s* prev;
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/**
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* Next pointer for garbage collection
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* linked list.
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*/
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struct libab_ref_count_s* next;
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/**
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* Function used to visit child containers,
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* used by GC.
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*/
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libab_visit_function_ptr visit_children;
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};
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/**
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* A reference to a value.
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*/
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struct libab_ref_s {
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/**
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* Whether this reference is a strong reference.
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*/
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unsigned int strong : 1;
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/**
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* Whether this reference is a NULL reference.
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*/
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unsigned int null : 1;
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/**
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* The reference count struct keeping track
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* of how many references are pointing to the value.
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*/
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struct libab_ref_count_s* count;
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};
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typedef struct libab_ref_s libab_ref;
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typedef struct libab_ref_count_s libab_ref_count;
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/**
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* Creates a new referene, using the given data and free function.
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* @param ref the reference to initialize with the given data.
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* @param data the data to reference count.
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* @param free_func the function to use to realease the data when refcount
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* reaches 0.
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* @return the result of the construction of the reference.
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*/
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libab_result libab_ref_new(libab_ref* ref, void* data,
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void (*free_func)(void* data));
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/**
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* Creates a reference to NULL. This does
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* not require a memory allocation.
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* @param ref the reference to initialize with null.
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*/
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void libab_ref_null(libab_ref* ref);
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/**
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* Turns the given reference into a weak reference,
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* making it not keep the data allocated.
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*/
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void libab_ref_weaken(libab_ref* ref);
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/**
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* Releases this particular reference to the data.
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* This doesn't necessarily free the underlying data.
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*/
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void libab_ref_free(libab_ref* ref);
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/**
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* Copies this reference, thereby increasing the reference count.
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*/
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void libab_ref_copy(const libab_ref* ref, libab_ref* into);
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/**
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* Swaps the contents of two references.
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*/
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void libab_ref_swap(libab_ref* left, libab_ref* right);
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/**
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* Function that can be passed in to refcount to simply use free
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* when the refcount reaches 0.
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*/
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void libab_ref_data_free(void*);
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/**
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* Gets the value of the reference.
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*/
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void* libab_ref_get(const libab_ref* ref);
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#endif
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